1. Field of the Invention
The present invention relates to a process and device for determining the composition of an alcohol-petrol mixture, adapted to the automatic regulation of engines fed with fuel mixtures having a variable alcohol content.
In order to use the different types of fuels which will be commercially available in the future, flexible engines using polyfuels will have to have an integrated system for adapting to the different fuels, or to the mixtures of the different fuel formulations, on the one hand, and for automatically adjusting the fuel/air ratio and the ignition, on the other hand.
The essential object of the present invention is to satisfy these different requirements.
To resolve the problem thus posed, the invention provides a process for determining the composition of an alcohol-petrol mixture, in which a light beam is emitted through the mixture and the degree to which this beam is absorbed by the mixture is determined for at least one wave length chosen in the wave length range corresponding to the near infra-red, this degree of absorption being related to the alcohol content of the mixture.
By "near infra-red" is to be understood the zone of the light spectrum corresponding to a wave length between 0.7 and 1.7 micro (700 to 1700 nanometers).
2. Description of the Prior Art
French Pat. No. 2,487,010 and the article entitled "Probleemloze toepassing van alcoholbenzine-mengsels in auto's" published in March 1981 on pages 117-122 of number 3 (volume 36) of the revue "Polytechnisch Tijdschrift Werktuigbouw" describe a device for measuring the percentage of alcohol in the fuel. This device uses light transmission in a glass column, but it does not define the light absorbed by the fuel in the near infra-red. More generally, it is not known in the Prior Art to use the absorption of light in the near infra-red by an alcohol-petrol mixture for determining the composition of this mixture.
The Prior Art may be illustrated by the U.S. Pat. Nos. 4,369,736, 3,996,785, 4,031,864 and 4,321,465 and British Pat. No. 1,554,309.